Muffler for telephone-transmitters.



G. KRAGKBR. MUEILER FOR TELEPHONE TRANSMITTERS.

APPLICATION FILED DBO. 28, 1907.

- Patentsd Oct. 13, 1908.

UNITED sTAirEs Barnum orrron.

MUFFLER FOR '.IELEPHONE-TIRANSMII'l'TIERS.b

No. 901,1o.

Specification of Letters Patent.

Patented Oct. 13, 1908.

Application filed December 28, 1907. Serial No. 408,392.

To all whom it may concern.:

Bc it known that l, (irnonun Knacken, a

citizen of the United States, residing in the city and county ofI Philadelphia, State of Pennsylvania, have invented a new and useful Mutller for '.Ielephone-'lransniitters, of which the following is a specifica-tion.

This invention relates to attachments for telephones and consists of al device for preventing telephone conversation being heard by anyone standing in the vicinity of a transmitter when in use.

lt further consists of a device in which the sound is completely muliled within the instrument and no sound waves escape to the exterior thereof.

It still further consists of a sound muler, which may be detachably secured to any type of telephone transmitter and communicates by suitable air passages with the outside, and may therefore be used without any inconvenience in breathing.

For the purpose of explaining my invention, the accompanying drawing illustrates a satisfactory reduction of the same to practice, but the important instrumentalities thereof may be varied, and so it is to be understood that the invention is not limited to the specific arrangement and organization shown and described.

Figure 1 represents a perspective vlew of my novel mnl'ller. Fig. 2 represents a ver-l tical section through the same. Fig. 3 represents a View of the sound deadening means. Fig. 4 represents a section on line -'m of Fig. 2.

Similar letters of reference indicate corresponding parts in thegures.

Referring to the drawings 1 represents a casing, the side walls 2 and 3 of which are provided with openings 4 and 5 located in alinement with each other, in order to form a passage directly through the casing -while adjacent to both openings 4 and 5,

and preferably formed integral with the casing are extensions 6 and 7, the former of which is adapted to form a mouth piece 8, and the latter, 7 is adapted for attachment to a telephone transmitter. These eXtensions are lined with a suitable sound-deadening material 9, such as rubber or the like, the same, on the mouth piece, being extended around the edge to form a cushion guard over the mouth piece. Suitably secured to the extension 7, is a fastening flap or band 10 preferably formed of elastic material,

which may be stretched to fit over a mouth piece of an ordinary telephone transmitter and securely fasten the muiiier thereto.

In llig. 2 the device is shown secured to a telephone transmitter which is held in contact with the side wall 3 by means of the elas-` tic material 10 thereby securing the device accurately in position, but of course it will be understood that applicant is not to be limited to any ].)articular positioning of the transmitter' since the device will operate successfully as long as the opening for the month piece 8 is in a-linement with the transmitter.

Mounted within the casing, is a second sound-.deadening device shown as a spiral member 11, the function of which is to so reduce the sound or vibration in the interior of the casing as to prevent any sound reaching the exterior thereof. Apertures 12 are provided in the casing communicating with v the channel formed by the spiral, whereby air may enter the interior of the muffler, so

that the device may be used without interferin(1r with breathin The spiral 11 is preferably formed of ru ber or like sound-deadening material, and in the present instance, is divided into separate chambers 13 and 14 by a partition 15, which also serves to preserve a space between the convolutions of the spiral, though it will be apparent that this partition may be omitted, and simply one sound chamber' be formed. This device is designed to be attached to the transmitter of an ordinary telephone, and when a person talks into the mouth piece '8, the sound waves are carried without interference against the diaphragm of the transmitter, while the spiral efectually breaks-up the sound and prevents a-ny one standing in the Vicinity of the telephone hearing what is spoken into the muiiier.

It is well known that in the present use of the telephone, that in the majority of cases, the instruments are located in public places, and any one in the vicinity is able to hear eX- actly what a person using the telephone is saying. By the aid of this simple muffler, a person may talk in the ordinary tone through the telephone without the slightest inconvenience, and at the same time, nothing said by that person can be distinguished by any one standing close by.

The sides of the mouth piece 8 converge upwardly, so as to inclose the nose of the speaker and make a close joint with the contiguous portions of the face, thus preventing the escape of sound thereat, while as both nose and mouth are within said piece 8, breathing is properly permitted owing to the channel formed by the secondary sounddeadening device and the apertures o'r ports 12, which latter communicate With the at mosphere, the effect of which is evident.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, iszl l. In a device of the character described, a

casing having openings therein, a mouth piece of greater diameter than said openin s secured to said casing in alinenient with said openings, a sound-deadening material in said mouth piece and casing, an auxiliary cham` ber formed in said casing, an inlet and an outlet for said auxiliary chamber, a longi tudinally disposed spiral partition between said inlet and outlet, and means for detachably securing the device to a telephone transmitter.

2. In a device of the character described, a casing having openings therein, a V-shaped mouth piece of greater diameter than said openings secured to said casing in :ilincment with said openings, a souml-dczulcning material 1n said mouth piece and casing, an

auxiliary chamber in said casing, an inlet 'and an outlet for sald auxlhary chamber, a

longitudinally disposed s iral partition be tween said inlet and out et, and means for detachably securing the device to a telephone transmitter.

3. In a device of the character described, a casing having openings therein, u V-shaped mouth piece secured to said casing in :illnement with said openings, an auxiliary chamber in said casing, an inlet and an outlet therefor colinnunicating respectively with the interior and exterior of said casing, a longitudinally disposed spiral partition in said chamber, a sound-deadening material forming a lining for said device, and an elastic member for detachably securing the device to a telephone transmitter.

GEORGE KRAOKER.

Vitnesses:

ROBERT M. BARR, HARRY C. DALTON. 

